1. Field of the Invention
This invention relates generally to liquid dispensers, and more particularly to dispensers of the type intended for ophthalmic applications.
2. Description of the Related Art Including Information Disclosed Under 37 CFR .sctn..sctn.1.97-1.98
The following patents are cited as being of interest, and together with the citations made against each, as well as the patents noted in some of the respective preambles, are considered to be a sampling of prior, known dispenser constructions of the kind typically used in the field of ophthalmology.
U.S. Patents Nos.: 3,409,009, 3,872,866, 3,934,590, 4,002,168, 4,085,750, 4,733,802, 5,154,710, 5,221,027 British Patent No. 971,137.
With specific reference to the above identified 9 patents, U.S. Pat. No. 5,221,027, discloses a shield member for an eye dropper nozzle, to minimize possible damage thereto and contamination thereof. In the embodiment of FIG. 7, a semicircular shield is employed, supported by two upstanding fingers. A cup-like shield is shown in FIG. 2, whereas a shield comprising multiple upstanding fingers is illustrated in FIG. 3.
U.S. Pat. No. 4,002,168 discloses a variety of guard constructions for ophthalmic containers, mostly in the form of ring structures which perform a double function, namely positioning the container over the eye during application, and minimizing inadvertent contact with the container nozzle, and resultant contamination.
U.S. Pat. No. 3,409,009 discloses a dispenser with integral eye cup, and a metering valve for controlling the quantity of liquid discharged.
U.S. Pat. No. 4,733,802 shows a dispenser system which utilizes a spacer cup for positioning the container over the eye, and which cup has a finger notch to facilitate pulling one eyelid away, thus exposing the eyeball directly to receive the intended medicinal product.
U.S. Pat. No. 5,154,710 involves multiple dispenser constructions having various forms of spacer cups that position the dispenser over the eye of the user.
U.S. Pat. Nos. 3,872,866 and 3,934,590 illustrate dispensers employing support sleeves or collars having projecting fingers, to facilitate positioning in anticipation of the application of eyedrops.
U.S. Pat. No. 4,085,750 shows an attachment for a container wherein spring fingers on the attachment purportedly assist the user in spreading the (upper and lower) eyelids just prior to application of the eyedrops.
British Patent No. 971,137 discloses several forms of spacer guards for a bottle. In FIGS. 1 and 2, for example, there is provided a single piece guard comprising a bridge for supporting the bottle. FIG. 3 illustrates a design wherein the bottle is nestable in the bridge, for storage purposes. FIGS. 7-9 show a pair of pivoted arms which operate to position the bottle for application of drops to the eye of a user.
While the problem of product integrity is always of concern in the container field, this is especially so in the case of ophthalmic solutions and medicaments, for the reason that inadvertent contamination can lead to serious problems of eye infection and/or inflammation. Due to the proximity of the eye to the brain and to the multiple sinus cavities in and around the nose, it is incumbent upon both the pharmaceutical manufacturer as well as the consumer, to exercise the utmost care in preserving the antiseptic condition of eye solutions.
An existing closure cap construction currently in use is of a type having a base cap with screw threads that enable the base cap to be screwed onto the threaded neck of a plastic squeeze bottle, and a convergent upstanding spout on the base cap, with a small opening at the crest of the spout. A closure cap is provided, adapted to snap over the spout. An elongate integral web attaches the closure cap to the base cap, which facilitates use by the consumer, and also serves the important function of keeping the closure cap captive on the base cap, as opposed to a construction where the closure cap is completely removed and placed on a contaminated surface such as a table or sink.
One of the problems with the construction just described is that in use, the consumer lifts the closure cap with the tip of his finger, to pry it off the base cap. If care is not exercised, the likelihood exists of the tip of the finger inadvertently rubbing past the opening of the spout, thereby contaminating the adjacent surface, and possibly any residual liquid that may have collected around the spout and which has been retained thereon, by capillarity.
The problem is compounded in that the consumer does not become aware of the potential contamination when he initially grasps the dispenser because the closure cap hides or conceals the discharge opening. By the time that the consumer has pried the closure cap off, he may already have inadvertently brushed against the spout.
Use of mild chemical means (preservatives) to neutralize bacteria in such eye solutions, though frequently practiced, has not met with wide acceptance. Such chemical means are expensive, and can possibly interfere with the intended action of the eye solution and thus thwart the therapeutic effect; alternately, chemicals of the type noted can become unstable, especially over periods of several months. Their intended effect can thus be jeopardized under such circumstances.
Several manufacturers have resorted to the use of special filter screens, employing typically a pore size of 0.4 microns, and where the filter is treated with a bacteriostatic medium such as silver. Special valve structures have been devised, by which air drawn into a squeeze bottle immediately following dispensing, are channelled through a normally-closed, combined valve-and-filter unit.
Prior experience has dictated that maintaining sterility is best accomplished through time-tested packaging techniques meticulously followed by the pharmaceutical manufacturer, coupled with careful and attentive handling of the dispenser by the ultimate user, the consumer.
Although most consumers are aware of the need to maintain sterility in eye solutions, reliance on their expertise in so doing represents somewhat of a compromise, even under so-called optimum conditions.
Many of the prior art dispensers are physically cumbersome, and/or awkward to use. Where multi-piece components are employed and physical re-positioning of support arms or support sleeves is involved, the likelihood of contamination increases.